In the present pathological examination, a pathological sample (object) is directly observed with a human eye using an optical microscope. In recent years, something called a virtual microscope is used, which captures a pathological sample as image data and enables it to be observed on a display. Since the virtual microscope enables the image data of the pathological sample to be observed on the display, a plurality of people can observe it at the same time. Moreover, this virtual microscope has many advantages, for example a diagnosis can be requested by sharing the image data with a distant pathologist. This method, however, needs a long time to take an image of a pathological sample and to capture its image data.
One factor taking a long time is that a large image-pickup range of a pathological sample has to be captured as image data by using a narrow image-pickup area of a microscope. For a narrow image-pickup area of a microscope, it is required to take images multiple times or through scanning and to synthesize them into one image. An (image-pickup) optical system having a wide image-pickup area is required in order to make the number of shots smaller and to make an image capturing time period shorter than ever.
In the observation of the pathological sample, as the wide image-pickup area is required, an optical system having a high resolution in a viewable area is required.
Japanese Patent Publication No. S60-034737 discloses an objective lens of a microscope which includes a dioptric optical system, reduces aberrations well in the entire visible light range, and is suitable for observing a biologic cell or anything. Moreover, Japanese Domestic Publication of International Patent Application No. 2007-514179 discloses a catadioptric imaging system for a broadband microscope which includes a catadioptric optical system having a high resolution in the entire visible light range and is configured to detect defects in an integrated circuit or a photomask. WO00/39623 discloses a catadioptric imaging system which is suitable for manufacturing a semiconductor device and configured to expose micro patterns on a wide area with light of an ultraviolet wavelength region.
However, the objective lens of the microscope disclosed in Japanese Patent Publication No. S60-034737 reduces aberrations well in the entire visible light range, but the size of the observation area is not sufficient.
Moreover, the catadioptric imaging system disclosed in Japanese Domestic Publication of International Patent Application No. 2007-514179 reduces aberrations well in the entire visible light range and provides high resolution, but the size of the observation area is not sufficient.
The catadioptric imaging system disclosed in WO00/39623 provides a high resolution, but a wavelength region which corrects aberrations well is not sufficient.
Accordingly, the present invention provides a catadioptric optical system configured to correct aberrations well in the entire visible light range and to provide a high resolution in a wide image-pickup area, and an image-pickup apparatus having the same.